Electric signaling



Jan. 26, 1943 M. E. MOHR 2,309,525

ELECTRIC SIGNALING Filed Jan. 21, 1941 2 Sheets-Sheet 2 36 l i 68 r 3.9

05 III 'IHIIIII "Hg-l I m wwv A 7' TORNLV trolling the impulses produced by the Patented Jan. 26. 1943 ELECTRIC SIGNALING Milton E. Mohr,

Jamaica, N. Y., assignor to Bel! Telephone Laboratories, Incorporated, New

York, N. Y., a corporation of New York Application January 21, 1941, Serial No. 375,201 7 Claims. (Cl. 250-427) This invention relates to signaling and particularly to the generation and transmission of electric signals and impulses.

An object of the invention is to obtain signaling impulses which are accurately fixed in time. Another object is to obtain impulses which have amplitudes that are substantially uniform throughout their duration. the invention is to control with a high degree of accuracy the phase or the position in time in which these impulses occur.

These objects are realized in accordance with the present invention by means of animpulse generating system comprising two discharge tubes and means for applying alternating voltages to the control and main gaps of these tubes in such phases that one tube ionlzes first to cause the flow of current in a common resistance element and the other tube ionizes a predetermined interval thereafter to neutralize the current flow in said resistance element. The desired impulse results from the flow of current in the resistance element, and its position and duration may be accurately controlled by controlling the phases of the voltages applied to said tubes.

A feature of the invention is an' impulse generating system in which the polarity of the impulses may be controlled by controlling the phases of the voltages applied to the tubes such that either tube ionizes first and the other tube ionizes a predetermined interval thereafter.

These and other features of the invention will be described more fully in the following detailed specification.

In the drawings accompanying the tion:

Fig. 1 discloses an impulse generating system incorporating the features of this invention;

Fig. 2 shows a phase shifting network for congenerator;

Figs. 3, 4 and are graphs showing the shape, duration and other characteristics of the impulses; and

Fig. 6 is a diagram of a signaling system incorporating the impulse generator.

The generating system disclosed in Fig. 1 comprises a supply source of alternating current I having any desired voltage and frequency. The supply source I is connected to a phase producing mechanism 2 which may be well-known character. The phase mechanism 2 has three supply circuits 3, 4 and 5, which supply voltage of the desired phases and of the same frequency as the source I. The supply circuit 3 is connected to the primary winding 6 of a transspecifica- Another object of of any suitable and r is preferred. Also these If, therefore, one

plies voltage through the has two secondary windings 1 and winding 1 is connected former which 8. The upper terminalof through a resistance element 9 to the cathode ID of a space discharge tube II. The lower terminal of minding I is connected to the negative pole of battery I2, and the grounded positive pole of this battery is connected through a common resistance element I3 to the anode I4 of the tube II. The lower terminal of the winding 8 is connected through a resistance element l5 to the anode I6 of discharge tube l1, and the upper terminal of winding 8 is connected to the positive pole of battery IS. The grounded negative pole of this battery is connected through the common resistance element l3 to the cathode IQ of the tube H.

The discharge tubes II and Il may be of any suitable type, but the well-known gas-filled tube tubes may have either hot or cold cathodes. The ionizing or control gaps of these tubes 'are supplied with voltages from the supply circuits 4 and 5. More specifically, the supply circuit 4 is connected across the gap formed by the cathode l0 and the control electrode 20 of the tube II, a resistance element 2| being included in series with this circuit.

Likewise, the supply circuit 5 is connected across the gap formed by the cathode l9 and control electrode 22 of tube IT, a resistance 23 being included in this circuit.

The output terminals 24 and 25 of the generating system are connected to impulse circuit 26, and the impulses are produced by discharging one of the tubes to set upa voltage across the common resistance element l3 and by discharging; the other tube a predetermined time thereafter to neutralize this voltage and thereby terminate the impulse. The supply circuit 3 suptransformer windings 1 and 8 to the main or anode gap circuits of the tubes H and I1, respectively, and the supply circuits 4 and 5 supply the controlgap voltages to 'cause the ionization of these tubes at the proper times.

For some purposes it is desirable to have impulses of substantially uniform amplitude throughout their duration. This may be achieved by producing impulses in that region of the voltage wave appearing in the supply circuit 3 where the rate of change islsmallest, namely in the region of the maximum instantaneous value.

the time the wave of the supply source 3 is approaching its maximum value and the other tub is discharged as the wave of the supply source of the tubes is discharged atv I I and I 1 during a hall cycle of the supply source 3 if common resistance I3 were omitted and the tubes II and I1 conducted during the respective half cycles of the source. The phases of the By properly selecting the phases of circuits 4 and 5 with, respect to the phase of circuit 3 the position and duration of the impulse may be controlled at will. That is to say, the impulse may be produced at any pointin the half cycle of the supply source 3, and the duration of the impulse sources 3 and 4 are so selected that the voltage \1 across the gap IIl-23 reaches the ionizing value of the tube II at the instant the voltage of the source 3 reaches the value represented by the angle 01 illustrated in Figs; ,3 and 4. Assumingthe source 3 to be in the half cycle aiding the direct current sources I2 and I8, current now flows in the anode circuit of the tube II. This,

ance element I3 rises abruptly from zero value to the ordinate value 28 (Fig. 3) and continues at approximately this value while the waveof the source 3 is passing through its maximum ordinate. During this period of current flow in the resistance I3 the wave,of the supply source 5 is approaching the ionizing value of the tube I1. The phase of the source 5 is so selected that the tube I1 ionizes at the desired predetermined interval following the ionization of the tube II, which may be at the angle 02. Current now flows in the anode circuit of tube I1, traceable from the positive pole of battery I8 through the winding 8, resistance I5, anode I6, cathode I3, resistance element I3 to the negative pole of battery I8.

It will be noted that the voltage across the 3 may be varied at will.

It is also possible by selecting the phases of circuits 4 and 5 to cause tube I1 to discharge first to commence the impulse and to cause the subsequent discharge of tube II to end the impulse. When the tubes are discharged in this order the impulses produced are of positive polarity.

If the phases of circuits 3, 4 and 5 are fixed by the phase producing mechanism 2 and it is desired to vary the length of the impulses from time to time, this may be accomplished by inserting a variable phase shifting network in the control gap circuit of one of the tubes, such as the tube I1 in Fig. 1. Such a phase shifting network is illustrated in Fig. 2. The control gap circuit of the tube 32 of Fig. 2 is substantially the same as that of the tube shown in Fig. 1, except that a variable resistance 33 and a variable condenser 34 have been added. By varying the resistance 33 and the condenser 34 the phase angle of the voltage wave supplied by the circuit 35 may be varied to control the length of the impulse.

- Fig. 6 illustrates one of the many useful applications of the impulse generating system shown in Fig. 1. Assume, for example, that it is desired to transmit a plurality of diflerent signals over the single transmitting conductor 36. At the transmitting end of the line a source of alternating current 31 is provided together with a suitable phase generator 38 whereby a plurality of different phases are derived from the source resistance I3 resulting from the ionization of Assuming the opposing voltage is just sufilcient to completely neutralize the current'fiow inre-, sistance I3, the resultant cancellation of the voltage across this resistance causes the current in the remaining part of the anode circuit of tube II to rise abruptly to the ordinate value 23 in Fi 3. Also since no voltage appears across the resistance element I3 the current in the anode circuit of tube I1 rises abruptly to the ordinate 33 of Fig. 4. Since in the common re sistance I3 the anode current of tube I1 represented by the ordinate 33 is in opposition to the anode current of the tube II, represented by the ordinate 23, the subtraction of these ordinates gives the graph of Fig. 5, representing the completed impulse. Stated in other words, the discharge of the tube I1 sets up a voltage across the resistance I3 equal and opposite to the voltage set up across. this resistance by the tube II, whereby the current ceases to flow, and the impulse is terminated. The left-hand terminal of the common resistance element I3 is grounded, and the right-hand terminal is connected to the output terminal 24 of the generating system. Therefore, during the interval between angles" 01 and 02, when current is flowing from left to right in the resistance element I3, an impulse of negative potential is produced on the terminal, and an impulse of corresponding polarity flows in the impulse circuit 26.

36 and to source H.

31. These phases, of which there may be ten different sets of three phases, appear in the ten groups of phase supply circuits 33, 43, H, 42, 43. Each groupof three phase supply circuits serves an impulse generator, such as the generators 44, 45, 4B, 41, 48, each of these generators being similar to the one disclosed in Fig. 1. In this manner generators 44, 45, 46, etc., produce impulses of ten different phases in their output circuits 43, 50, 5|, etc. These output circuits are connected to the anodes. of the respective tubes 68, 63, 10, etc., which serve to isolate the impulse generators from each other. The cathodes of the tubes are connected to the signal conductor The control electrodes of the tubes are connected through resistances to thecontacts of switches 52, 53, 54, etc., and the movable elements of these switches are connected to battery 12.

When it is desired to transmit a signal over the conductor 36, one or more of the impulse generators at the transmitting'end are connected to the line 35 by means of the switches 52, 53, 54, etc. The operated switches close ionizing circuits for the associated tubes, and impulses of the corresponding phases are sent through these tubes and over the line 36. At the receiving end of the system these incoming impulses" are all applied to the electrodes of ten register tubes 55, 56, 51, 58, 59. Also at the receiving station ten impulse generators 60, 6|, 62, 63, 64 are provided, one for each of the register tubes 55. 56, 51, etc. These generators are supplied with voltages of difierent phases by the phase producing device 65, which in turn is supplied with energy from a source 66 having the same fremoney as the source 31. Each of the generators 30, BI, 52, etc., generates impulses of one of the en different phases and applies these impulses .o the electrodes of the .ubes 55, 56, 51, etc. If the generators 44, 45, 16, etc., produce impulses of positive polarity and the generators 60, BI, 62, etc., of negative polarlty, it is possible to select and ionize any one or more of the register tubes by applying to the single conductor 36 from the transmitting end impulses of the corresponding phases.

Register tubes suitable for use in a system of this kind are disclosed in the patent to W. H. T. Holden, No. 2,285,815 of June 9, 1942. The Holden patent also discloses impulse generators for generating impulses of opposite polarities.

Many other useful applications will appear for the impulse. generator disclosed herein. For example, the square shaped impulses produced by this generator may be employed in the generation of harmonic voltages.

What is claimed is:

1. The combination in an impulse system of a discharge tube having a control gap and a main gap, a second discharge tube having a control gap and a main gap, a discharge circuit for the main gap of the first tube, a discharge circuit for the main gap of th second tube, an impedance element included in common in both of said discharge circuits, an impulse conductor including said impedance element, means for ionizing the control gap of the first tube, means effective a predetermined interval thereafter for ionizing the control gap of said second tube, means responsive to the ionization of said first tube for causing current to flow in the discharge circuit thereof, the voltage across said impedance element resulting from said current flow serving to produce an impulse in said conductor, and means responsive to the ionization of said second tube for causing current to flow in the discharge circuit thereof, the voltage across said impedance element resulting from the current flow in said second discharge circuit serving to oppose the first voltage across said element to terminate said impulse.

2. The combination inan impulse system of a discharge tube having a control electrode and an anode, a second discharge for said tubes, a resistance element included in each of said discharge circuits, a supply source for producing alternating voltage waves, means for applying said waves to said anodes, an impulse circuit including said resistance element, means for applying an alternating voltage of a given phase to the control electrode of said first tube for ionizing the same when the voltage of the anode is near its maximum value, said anode voltage causing current to flow in. the discharge tube to produce a voltage" element, the voltage across circuit of said first across said resistance I said element serving to produce an impulse in said impulse circuit, and means for applying an alternating voltage of a different phase to the control electrode of said second tube for ionizing the same a definite interval following ionization corresponding register main discharge gaps, means for applying .voltages of different phases to said control gaps to cause either one of said tubes to ionize first and the other tube to ionize a definite time thereafter, an impulse circuit having a resistance element therein, means responsive to the ionizatiorrof the first tube for causing current to flow in the main gap thereof and through said resistance element in a. given direction, the fiow of current in said element producing an impulse in said impulse circuit, and means responsive to the ionization of the second tube for causing current to flow in the main gap thereof, the current flow in said second tube opposing the current in said resistance element to cause the cessation of said impulse.

4. The combination in an impulse system of two discharge tubes having control gaps and main discharge gaps, means for applying voltages of different phases to said control gaps to cause either one of said tubes to ionize first and the other tube to ionize a definite time thereafter, an

tube having a control electrode and an anode, discharge circuits of the first tube, the anode voltag of aid ond tube causing current to flow in the discharge circuit thereof to produce a voltage opposing and neutralizing the first-mentioned voltage across said resistance element to terminate said impulse.

3. The combination in an impulse system of two discharge tubes having control gaps and impulse circuit having a resistance element therein, means responsive to the ionization of the first tube for causing current to flow in the main gap thereof and through saidresistance element in either direction according to which of the tubes is ionized first, the flow of current in said element'producing an impulse in said impulse circuit, the polarity of said impulse depending on the direction of current in said element, and means responsive to the ionization of the second tube for causing current to fiow in the main gap thereof, the current flow in said second tube opposing the current ment to cause the cessation of said impulse.

5'. The combination in an impulse system of two discharge tubes having control gaps and main discharge gaps, means for applying voltages of a given frequecny and of different phases to said control gaps to cause ionize first and the other tube to ionize a definite time thereafter, an impulse circuit having a resistance element therein, a supply source of alternating voltage of said given frequency, means including said supply source effective upon the ionization of the first tube for causing current to fiow in the main gap thereof and through 'said resistance element in a given direction, the

ducing an impulse in said impulse circuit, and means including said supply source effective upon the ionization of the second tube for causing current to flow in the main gap thereof, the current flow in said second tube neutralizing the current in said resistance element to cause the cessation of said impulse.

6. The combination in an impulse system of two discharge tubes having control gaps and main discharge gaps, means for supplying voltages of a given frequency and of different phases to said control gaps to cause one of said tubes to ionize first and the other tube to ionize a predetermined time thereafter, an impulse 'cir cuit having a resistance element therein, means responsive to the ionization of the-first tube for causing current to flow in the main gap thereof and through said resistance element to produce an impulse in said impulse circuit; means reopposing the current flow in said resistance element to cause the cessation of said'impulse, and means for varying the phase of the voltage apin said resistance eleone of said tubes to plied to the control gap of one of said tubes for varying the length of said predetermined interval. 1 s

7. The combination in an impulse system of two discharge tubes having control gaps and main discharge gaps, sources .of alternating after a deflnite'time interval by the ionization of the other tube depending on the relative phases of the applied sources, an impulse cir-.

cult having a resistance element therein, means responsive to each ionization of the flrst'tube to ionize for causing current to flow in the main gap thereof and through said resistance element, each flow of current in said element producing an impulse in said impulse circuit, and means responsive to each ionization of the second tube to ionize for causing current to flow in the main gap thereof, the current flow in said second tube opposing the current in said resistance element tocause the cessation oi. the impulse;

' ramroN- n. MOHR. 

